以新穎銥錯合物染料製備高效率可乾、溼式製作之綠光有機發光二極體

有機發光二極體 (Organic Light Emitting Diode, OLED)，被稱作是終極的顯示技術，亦可能是史上最佳的照明光源；高效率可以使此等元件節能，並呈現較長壽命；而其整體效率高低，端看紅、藍、綠三發光體的效率而定；在這當中，因為人眼對綠光的感受度最高，使得綠光 OLED 對元件整體的效率表現影響最大；又為考量製作成本，研發一個可同時適用於乾式與溼式製程的高效率綠光發光體，乃至關重要；有鑑於此，本研究探索利用一新穎綠光銥金屬錯合物發光體，bis [5-methyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin-6-one]iridium (acetyl acetonate)，以製作OLED元件；在以4,4'-bis(carbazol-9-yl) biphenyl 當作主體材料時，在亮度 1,000 cd m-2 的情況下，以乾式製作的此一綠光元件，其電流效率為77 cd A-1，外部量子效率 21%，能量效率 64 lm W-1；以濕式製作時，其電流效率為 95 cd A-1，外部量子效率 26%，能量效率 69 lm W-1，為溼式製作綠光元件當中的世界紀錄；此元件高效率的原因，有至少以下二點：首先，此一綠磷光染料本身具備良好的電致發光活性，像是極短的激態生命期 (1.25μs) 及相當高的量子產率 (69%)；再者，元件發光層當中，搭配具有電子注入能井的主體材料，以促使身為少數載子的電子更加容易注入，以與大量注入的電洞平衡，增加再結合效率，進而提升放光效率。

關鍵字

綠光；銥錯合物；有機發光二極體

並列摘要

High efficiency green emission is crucial to the designs of energy-saving display and lighting. Efficient electroluminescent green emitters with both wet- and dry-process feasibility is highly desirable in order to realize, respectively, cost-effective large roll-to-roll manufacturing and high performance products. We demonstrate in this study high efficiency phosphorescent green organic light-emitting diodes with a novel iridium complex, bis[5-methyl-8-trifluoromethyl-5H-benzo(c)(1,5)naphthyridin- 6-one] iridium (acetyl acetonate), possessing both wet- and dry-process feasibility. The emitter exhibits a short excited-state lifetime, 1.25 μs, and a high quantum yield, 69%, due to the efficient intersystem crossing of the ground-state to the excited-state. Using 4,4’-bis(carbazol-9-yl) biphenyl as host for example, the device shows at 1,000 cd m-2 an external quantum efficiency (EQE) of 21%, current efficiency of 77 cd A-1 and power efficiency of 64 lm W-1 via vapor deposition, while 26% EQE, current efficiency of 77 cd A-1 and 69 lm W-1 by spin-coating, the highest among all reported wet-processed green organic light-emitting diodes. Besides the electroluminescence effective emitter, the high device efficiency may also be attributed to the employed device architecture enabling therein an electron trap to facilitate the injection of this minor carrier against that of hole, leading to a balanced carrier-injection, and hence a high carrier recombination and in turn a high device efficiency.

並列關鍵字

無資料

參考文獻

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以新穎銥錯合物染料製備高效率可乾、溼式製作之綠光有機發光二極體

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